1. Field of the Invention
The present invention relates to a paper feeding system and picking system used therefor used in a printer and others.
2. Description of the Related Art
In the prior art paper feeding system of a printer, a picking roller for feeding paper one by one is rotationally driven by receiving driving force of a motor that simultaneously drives a feed roller and a discharge roller and always abuts with paper. Due to that, when the paper is not fed, the rotation of the picking roller has to be stopped, and to that end, an electromagnetic clutch is provided in the middle of transmission of the driving force from the motor to the picking roller to be able to transmit or to interrupt the driving force. A corner nail installed in a fixed manner also engages with the front corner portion of the paper placed on a hopper plate biased upwardly by biasing means.
Accordingly, there has been problems in the prior art that its structure became complex and it was expensive because the mechanism of electromagnetic clutch and others for controlling transmission or interruption of the driving force were necessary. Moreover, there has been such a problem that because the corner nail installed in a fixed manner engages with the corner of the paper, the surface of the corner of the paper is pressed by the corner nail and the paper cannot curl easily when the paper is fed by being separated one by one. Hence such problems that the feeding becomes insecure, the paper cannot be easily disengaged from the corner nail even if it curled, the curling becomes unnecessarily large and a large space for the curling at the top and bottom has to be taken were brought about.
On the other hand, in printer and copier systems, a picking system is installed by which the top paper is taken out from the paper holder like a paper cassette and is sent to the printing section by conveyer rollers and the like.
In the publicly known picking system, the picking roller is generally adapted to transmit or interrupt driving force from a driving means by an electromagnetic clutch.
However, the picking system as mentioned above had such problems that its production cost is high since it needs the electromagnetic clutch and that because the picking roller always abuts to paper in the paper holder, the picking roller becomes a drag in conveying the paper when the rotation of the picking roller is stopped after the paper is taken out of the paper holder.
Accordingly, a general object of the present invention is to eliminate the mechanism for interrupting the driving force for the picking roller to allow to lower the cost of the feeding system and to secure feeding of papers.
Another object of the present invention is to provide a picking system in which a picking roller abuts to paper only when the paper is taken out of the paper holder.